1) Field of Invention
The present invention relates to mounting implements on tractors. More particularly, this invention relates to mounting implements, such as mowers, on lawn and garden tractors. The invention is a quick hitch arrangement for raisably suspending the rear of a mower deck from the tractor frame.
2) Related Art
An implement draft frame for a lawn and garden tractor is disclosed by Erdman in U.S. Pat. No. 3,948,025. The draft frame includes a pair of rear draft arms pivotally connected to the tractor frame and a pair of rear draft brackets on the mower deck respectively. Laterally spaced mounting brackets rigidly attached to on the front of the tractor frame for attaching the implement. The front mounting brackets include a pair of forwardly opening receptacles. A rather complex bracket system is pinned to a pair of front draft towers on the front of the implement by spring loaded J-pins. The bracket structure attached to the front of the implement includes a pair of laterally spaced sins that can be rotated with a lever into the receptacles on the frame brackets. This mower deck mounting system is rather complex and requires a considerable number of moving parts.
A mower deck mounting system is disclosed by Kuhn et al. in U.S. Pat. No. 5,025,617. The system involves a parallel linkage lift mechanism that includes front and rear supports on the mower deck. A pair of laterally spaced rear support brackets on the mower deck includes spring-loaded J-pins, which have truncated legs. The truncated legs of the J-pins are connectable respectively with holes in corresponding laterally spaced lift arms, which are connected with the parallel linkage and the tractor frame. However, this system also requires fabrication and assembly of a considerable number of parts. The spring-loaded J-pin requires a spring, the pin, and a spring retaining means. Because the truncated leg of the J-pin fits into a relatively small hole in a fixed location on the lifting arm, the system requires a lost motion connector to accommodate movement of the mower deck over rough or uneven terrain. Although the system improved the state of the art, there are still challenges when attaching and removing the mower deck. The lifting arms and the brackets on the mower deck must be aligned rather precisely both laterally and vertically. The holes in the lifting arms must be at the proper height to receive the truncated portion of the J-pins. It is hard to make such fine adjustments by steering the tractor and raising or lowering the parallel linkage system. Consequently, a worker must physically lift, move and hold the mower deck while adjusting the height of the lift arms to the desired position. Due to the weight of the mower deck, this can be difficult for a single worker to accomplish without assistance from other workers or equipment.
It is therefore an object of the present invention to provide an improved system for mounting an implement such as a mower deck on a tractor.
It is a further object to provide a mower deck rear draft quick hitch arrangement that is less complex and yet more effective than existing arrangements.
It is another object to provide a mower deck rear draft quick hitch arrangement that reduces or eliminates the need for a separate lost motion connector.
It is another object to provide a mower deck rear draft quick hitch arrangement that uses the lifting and motive power of the tractor to hitch the rear of the mower deck to the frame.
It is a further object to provide a mower deck rear draft quick hitch arrangement that reduces reliance on moving parts such as spring-loaded pins.
It is a further object to provide a mower deck rear draft quick hitch arrangement that forgives some initial misalignment between the lifting arms and the rear draft tower brackets.
Another object of this invention is the provision of a quick hitch arrangement that is economical to produce, easy to use, durable, and reliable.
The mower deck mounting system of this invention includes at least one elongated rear draft lifting arm. Preferably two such lifting arms are included. The lifting arms have a first end that pivotally connects to the frame of the tractor, an intermediate portion that pivotally connects to the parallel linkage means, and a second forked end. The forked end has a pair of vertically spaced upper and lower tines or fingers thereon forming a closed-ended slot or space therebetween for slidably receiving a substantially horizontal pin stationarily mounted on the rear draft tower of the implement.
Also disclosed herein is a structure for supporting the mounting pin on the implement and guiding the lifting arms toward the pin. This structure includes a pair of laterally spaced upright guide members mounted on the implement for supporting the pin therebetween. Each guide member has a straight rear portion and a front portion that is angled away from the rear portion and away from the other guide member so as to correct for any minor lateral misalignment as the lifting arms approach the mounting pins. Similarly, the top portion of each guide member angles away from the other guide member for the same reason.